Men whose testosterone sat in the lowest fifth of the range were 18 per cent more likely to die of cancer in the years that followed. That is the headline figure from a pooled analysis of 11 long-running studies covering more than 26,000 men in Australia, the United States and Europe, published in The Lancet Healthy Longevity.
The bottom line: the number is a warning marker, not a verdict.
The work comes from the Androgens In Men Study, an international collaboration led by Professor Bu Yeap, an endocrinologist at The University of Western Australia. His team matched hormone measurements from blood samples taken earlier in life against what happened to the same men over the following decades. Follow-up in the individual studies ran at least five years. The hormones tracked included testosterone, dihydrotestosterone, sex hormone-binding globulin (SHBG) and luteinising hormone, which the pituitary gland makes to prompt the testes to produce testosterone.
“We wanted to know whether the concentration of these hormones in the blood was related to the risk of men being diagnosed with, or dying from, cancer into the future,” Yeap said.
Where the risk starts to climb
Yeap said healthy young men usually measure between 10 and 30 nanomoles per litre (nmol/L), and that levels tend to run lower in older men. Body mass index, physical activity and conditions such as diabetes can also move them.
The data showed deaths from cancer starting to rise once testosterone fell below 8.6 nmol/L. For a cancer diagnosis, the risk began to increase below 7.3 nmol/L. The gap held after the researchers adjusted for age and other health factors.
“This suggests low testosterone is an important biomarker, so it’s possible that looking at testosterone levels could help us identify men who might do poorly if they get cancer down the track,” Yeap said.
Prostate cancer broke the pattern
One cancer did not fit. Prostate cancer showed no link to the amount of testosterone a man’s body makes. Researchers have long wondered about that connection, since lowering testosterone is a treatment for the disease. “Based on our findings there’s no evidence they are related,” Yeap said.
Prostate cancer did track with two other hormones. Men with low SHBG and low luteinising hormone were at higher risk of being diagnosed with it. ScienceAlert noted that the result is a little surprising given how responsive the prostate is to testosterone, and that further study will be needed to explain it.
What men are told to do
Observational data of this kind cannot show cause and effect, and Yeap was direct that the findings are no reason to start taking testosterone. “While we’ve shown low levels are associated with increased risk, we haven’t got any evidence yet that actually giving men testosterone will reduce that risk,” he said.
His advice is a doctor’s visit. “If they are found for whatever reason to be low in testosterone, it’s important to go to the doctor for a full checkup,” he said. A checkup may turn up no sign of testicular disease, he added, but it might show other health issues or risk factors worth dealing with.
He also described the result as “a wake-up call and encouragement for men to engage in more healthy lifestyle behaviours, and to get regular, holistic checkups to stay on top of their health.”
Sources
- Low Testosterone Is Linked to a Higher Risk of Cancer, Study Finds
- Low testosterone linked to cancer risk in men
